1. Technical Field
The present invention relates in general to wireline survey tools and, in particular, to an improved system, method, and apparatus for enabling a wireline survey tool with roller knuckle joints to penetrate and survey highly inclined horizontal wells having an angle of inclination in excess of about 60° from vertical.
2. Description of the Related Art
In horizontal wells, surveys for well parameters, such as temperature and pressure, are typically conducted to identify casing leaks, free gas entry into perforations, etc. A conventional survey tool string has a shock absorber on its leading end, long weight stems (e.g., five to seven feet in axial length), standard knuckle joints, and exposed gauges for measuring the various well parameters.
It is not uncommon to encounter a horizontal inclination that exceeds 50° from the initial vertical orientation of the well. The ability to conduct surveys in these types of wells with a conventional wireline tool is proven, but is limited to inclinations of less than 60°. At inclinations of about 60° or more, the weight and flexibility of the survey tool string is insufficient to overcome the friction and interference between the survey tool string and the well. Moreover, if a wireline operator is inattentive when encountering such deviated conditions, the wireline can coil inside the downhole tubing of the well and be accidentally cut.
These problems make it difficult for production engineers to identify the condition of a well, especially in critical areas such as the interfaces of differing strata, in order to take the necessary action to avoid the loss of hydrocarbons. Thus, an improved solution for reaching highly inclined horizontal wells with wireline survey tools is needed.